Connecting your Pi to the internet when mobile

Question

So I am working on a project where I have torn away all the RC related parts of an older 1/10 scale Racing Buggy I had as a kid and replacing said parts with some Arduinos and a GPS to create a super rudimentary autonomous vehicle. I want to add in the Raspberry Pi Zero W as an on board base station for data logging and network control through a web app I'll design later on with my server.

My concern is that short of getting some kind of data-box from Verizon or AT&T and paying a terribly large monthly bill on a contract I don't want, I'm not sure of any other cheap options.

So what options do I have available to get the Pi on the cellular network that won't cost me an arm and a leg?

Answer 1

I think that Electron by Particle may be something what you are looking for. Electron allows you to build device that can connect to 2G or 3G mobile wireless network.

In one of the previous comments you mentioned that your data usage probably will not exceed a megabyte of data per month. With Electron you are charged monthly for the base rate which is $2.99 (includes first megabyte) and then $0.99 per any additional MB.

From technical point of view, Electron is connected to Particle's cloud and exchanges messages with it. Then you can control Electron through your web-app by sending HTTP requests from your web-app to Particle's cloud. Electron has GPIO pins (also for Serial/UART communication) so depends on your needs you can connect it with your Raspberry Pi - for more information go here.

In a general scenario communication between you and Electron should look like that:

1. write a function which handles command on Electron:

int callRaspberry(String command) {
    //handle communication here
}

2. register previous function during setup:

void setup()
{
   Particle.function("callRaspberry",callRaspberry);
}

3. make a request to Particle's cloud, to call the function on Electron:

curl https://api.particle.io/v1/devices/<DEVICE_ID>/callRaspberry \
  -d access_token=<YOUR_ACCESS_TOKEN> \
  -d arg=<COMMAND_VALUE>

More code examples can be found here.

I've also seen that Hologram provides similar devices to Electron and their service price is also cheaper. You can find some comparison here.

Answer 2

You got Sigfox or Lora that can be a possibility but, it's limited to few messages per day, so you wont be able to stream or to send real time command. And it's also not free, but it's cheap. But you can't have connection if you don't have an Internet provider or GSM provider.

I did a project once doing the same kind of stuff you want to do with Sigfox network, I had a server and send data to it with GPS location and sensors data. The location was shown using google map's javascript API. It wasn't hard work but it wasn't "streaming" location since Sigfox network isn't design for it. (count at least 15s per message)